Prefabricated plastic stairway and method of manufacture

ABSTRACT

This invention is a prefabricated molded or precast stairway and method of making the same and with such structure having a facing representing brick, stone or other desired ornamental finish.

United States Patent [151 3,706,170 Argraves et a]. 1 Dec. 19, 1972 [54 PREFABRICATED PLASTIC [56] References Cited STAIRWAY AND METHOD-0F UNITED STATES PATENTS MANUFACTURE 1,861,751 6/1932 Nlcols ..52/l89 1 Inventors: Nell Argravcs, Salem, 1,954,722 4/1934 Bateson m1. ..52/189 David Mann, Yarmouth, Mame 1,964,660 6/1934 Buzby ..52/l89 1,985,143 12/1934 Buffaloe ..52/189 [73] Asslgneef f; g i x 2,558,615 6/1951 Yoanson ..52/19ox by 2,697,931 12/1954 Schill ..52/1s9 F! d: 1 14,1970 [22] le Juy Primary ExaminerFrank L. Abbott [21] Appl. No.1 54,711 Assistant Examiner-Henry E. Raduazo 1 Att0rney-A. Yates Dowel] and A. Yates Dowel], Jr. 52 05.01. ..52/1s9,52/191,52/1s2 ABSTRACT 51 1111.01. ..E04r11/14,E04f11/00 v [58] Field of Search 52/190 188 189 191L182, Th1s mventlon 1s a prefabrrcated molded or precast stairway and method of making the same and with such structure having 21 facing representing brick, stone or other desired ornamental finish.

4 Claims, 28 Drawing Figures PATENTEDMB 1 1912 3. 706; 1 70 SHEET 1 0F 4 INVENTOR;

J rdfmh MA ATTORNEYS PAIENTED w: 1 m2 3; 706 170 SHEET 3 BF 4 H6: A? v HQ /4 E 33 I IIIIF lllllllllll j I l' E F/GIZO INVENTORJ ATTORNEY} BACKGROUND OF THE INVENTION 1. Field of the Invention The invention is in the field of static structures, precast stone-like components, static molds, plastic, block and earthenware apparatus.

2. Description of the Prior Art Various types of precast stairs with ornamental surfaces have been produced; however, these have failed to meet the demands for simplicity, practicality, time, labor, and material saving, and the like.

SUMMARY OF THE INVENTION AND OBJECTS In the execution of the invention the necessary forms are made and into them the desired ingredients are introduced and allowed to set and cure with or without additional heat, after-which the cast or molded units are removed from the forms and used to build the completed stairway. If the installation is to be done at a distance, the cast or molded units are packaged and shipped or transported unassembled to the desired location. The individual parts may be easily handled by a workman and require minimum space for transportationand storage. After installation the entire assembly can be moved by the use of equipmentfor handling heavy installations.

It is an object of the invention to provide individual precast complementary stair-forming units which can be manufactured and stored or readily handled and installed by one workman and which when so installed the structure will have a professional appearance.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective illustrating one application of the invention;

FIG. 2, a similar view with an added portion or extension;

FIG. 3, an exploded view of the assembly of FIG. 1;

FIG. 4, an exploded view of the extension of FIG. 2;

FIG. 5, a section on the line 5-5 of FIG. 1;

FIG. 6, a view on the line 66 of FIG. 5;

FIG. 7, a side elevation of the hollow form or mold for producing the side or support sections;

FIG. 8, a front elevation of the structure of FIG. 7;

FIG. 9, a side elevation of a closure member or backup plate for either side of the hollow form of FIG. 7;

FIG. 10, a front elevation of the structure of FIG. 9;

FIGS. 1 1 & 12 are plan and end views of the mold for the top member or platform;

FIGS. 13 and 14 are plan and end views of the mold for the tread;

FIGS. 15 & 16 are plan and end views of the riser;

FIGS. 17 & 18 are side elevation and end views of the grid for forming the design of the facade or surface finish on the side members;

FIGS. 19 & 20 are plan and end views of the grid for providing the finish on the front of the riser;

FIG. 21 is a perspective of a mold for the riser with reinforcing grid structure in place;

FIG. 22, a perspective of the mold after it is filled and the surface smoothed and finished;

FIG. 23, a perspective of the filled mold of FIG. 22 with the surface forming grid applied;

FIG. 24, a similar view with the grid removed;

FIG. 25, a perspective of the formed product removed from the mold and with grouting applied;

FIG. 26, a fragmentary enlarged perspective of a similar riser with an anchoring rod through the end;

FIG. 27, an enlarged fragmentary perspective illustrating the lower end portion of one of the side members with a spacer for supporting the riser; and

FIG. 28, a perspective of a modified form'of back-up plate similar to the structure of FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENT 30 With references to the drawings, as illustrated in FIG. 3, side members 10 are provided having a series of support portions 11, 12 and 13 disposed in offset generally parallel horizontal relationship with each other. Risers 14 are provided having longer and shorter portions l5'and 16 with a front facing 17. The longer portions 15 of the risers 14 are adapted to rest upon the horizontal portions 11 of the side members 10 so that the tops of such risers provide an extension of the horizontal support surface 12. A tread member 18 is mounted on support surfaces 12 and risers l4 and such tread member has a length at least as long as the risers. Each tread member has a reduced portion 19 which is disposed between the side members 10 in a position to underlie the next higher riser 14. The ends of the reduced portion 19 substantially abut the side members 10 and are connected thereto by mortar or other bonding agent. A cap or platform 20 rests at the top of the structure. If it is desiredto provide an extension of this cap or platform, an additional platform 20 may be supported on side members 22 having a front edge 23 adapted to abutthe rear edge of the side members 10. The complementary parts such as the side members, risers, treads and caps or platforms, preferably are provided with anchor bolts, pins or dowels 24 to insure solid connections between the parts.

In order to produce the side members, aside form 25 is provided, as illustrated in FIG. 7. This form is open at opposite sides and is adapted to be placed on a horizontal support or base, such as the base 26 illustrated in FIG. 9. One side of the base and form is up when the form is filled with plastic material and then the other side up for the opposite side member, as will be readily understood. In order to add flexibility, the form 25, as illustrated in FIG. 7, may be provided with vertical partitions 27 and 28 and horizontal partitions 29 and 30. By filling the space next to the stepped portions bounded by the partitions 27 and 30, the steps as illustrated in FIGS. 1, 2 and 3 may be produced consisting of two treads and a cap. If desired by filling in the space next to the stepped portions bounded by the partitions 28 and the a single step and cap may be produced. This is also true by filling in the step portions bounded by the partitions 29'and 27 as well as a single step and cap by filling in the part of the step bounded by the lower portion of the form 25 and the partition 30.

In order to provide for the molding or casting of the platform 20, a shallow pan 31 may be provided having a central reinforcing rib 32 and such pan may be filled with the plastic mix. The reinforcing rib 32 provides a corresponding recess in the cap or platform 20. In order to provide molds for the treads l8 and riser members l4, pans 33 and 34 are provided of the configuration of the treads and risers and a grid 35 may be applied to the surface of the mix in the pan 34 to form the ornamental front of the riser.

FIG. 17 illustrates a grid 36 by which an ornamental surface may be imparted to one of the side members, such grid having limiting bars 37, 38, 39 which limit the amount of penetration the grid makes into the mix in side form 25. A second grid with the parts the reverse of those in FIG. 17 is provided for omamenting the opposite side form. The grid of FIG. 19 likewise is provided with transverse bars 40 for limiting penetration of the grid.

In FIGS. 21-24 inclusive, there is illustrated a riser molding pan 34-with a reinforcing wire grid 46 shown in FIG. 21, the the pan empty, but filled with plastic mix in FIGS. 22, 23 and 24. In FIG. 23 the ornamenting grid 35 is shown with vibrators 41 resting thereon. In FIG. 24 the grid 35 has been removed leaving the ornamental surface depression, while in FIG. 25 the riser is illustrated removed from the pan and being provided with grouting 42 from a gun 43.

In FIG. 26 a slightly modified type of riser 14' is provided having dowel pins or projections 44 extending generally vertically from the ends of the longer portions and adapted to be received within openings (not shown) in cooperating side members 10, treads l8 and cap by which the riser canbe' anchored in place. In FIG. 27 the side member 10 may have a step or spacer plate 45 to make room for grouting around the same.

With reference to FIG. 28, a modified form of base 26' is provided having integral upstanding projections 46. In this modification the grid 35 can be omitted since the projections 46 will form the ornamental depressions which are later filled with grouting 42 after the plastic mix has hardened and has been removed from the side form 25.

It will be apparent from the foregoing that the desired number of forms are provided according to requirements withsufficient bottoms orbase members 26 according to the number of side forms desired tobe used at one time. After a bottom and side form are supplied with the mixture, the side form can be removed in a relatively short time leaving the set-up material on the bottom or base while the side form can be used again and again in this manner until the desired numberof side members are produced. It will be understood that in the production of the individual members, they may be moved into a storage area and allowed to set until cured and hardened or if desired the curing can be accelerated in any well known manner.

In the production of the mixture, it has been found that sifted sand or aggregate is mixed with Portland cement in dry state withfour parts of sand or aggregate to one part of cement and dye, such as for example one pound of red and one-half pound of brown dye may be added to the batch and after being thoroughly mixed water is added and mixed until the mixture is completely saturated but not soupy. Side forms and front forms preferably are oiled and placed on a level surface and a portion of the mixture is introduced into the mold after which the reinforcement is added and then the remainder of the mixture is added until the mold is filled. The upper surface of the mixture then is smoothed with a trowel and the ornamental surface providing grid is applied and vibrated until it is firmly integrated with the cement mixture. In other words, the

grid serves to stamp the surface to give it an ornamental appearance. The grid or stamp is left in the cement for approximately two hours or until the cement has congealed enough to hold its shape when the grid or stamp is lifted out leaving a smooth faced brick-like facade with joints between the same. Various parts are produced in this manner and the sides and fronts are left to dry for 48 hours or as long as necessary for proper curing and hardening. At the end of the hardening period the joints are filled with grouting or mortar cement whereupon after a relatively short period, such as one or two hours, the molded products are removed from the forms and left to cure approximately 12 days.

In the platform and treads the same consistency of cement and sand is used; however, dye is not needed. These forms are oiled to prevent sticking and are filled, reinforcing is inserted and the forms smoothed to the degree desired. In the case of the treads, they may have a roughened surface to prevent slipping in the rain or other adverse weather conditions. After the cement has set for approximately 2 hours, this slight roughing of the treads may be accomplished in any desired manner as by a stiff brush or the like, and the edges may be beveled with a trowel for a neat appearance. The treads and platform are left to ,dry. for 48 hours and then removed and allowed to cure for 12 days as indicated. After the curing of the several parts or individual units, they may be installed by the use of mortar and cement with bolts sunk into holes to connect the parts in assembled relation.

In assembling, the sides are erected and braced, holes are drilled in the sides supporting the front sections and also in the parts of the front sections that rest on the side. Mortar is applied freely to all contact points and bolts are left protruding from the cement filled holes on the side members. The front sectionis put into place bonding both sides together with a reinforcing bolt 44 in the center. The tread is next installed onto the relatively wide upper surfaces of the sides and front sections with mortar applied between the tread and the supporting surfaces with or without anchor bolts between the same. The second front is installed slightly different from the first due to the fact that there is a lip or extension on the back of the tread for the entire width of the steps thus giving more contact area and the front may also be secured merely by mortar at all contact points, although bolts may be employed if desired.

When the step is constructed to the final point of securing the platform in place, two bolts on each side preferably are used to secure the platform to the upper surfaces of the sides and mortar is applied freely to all contacting portions and the platform set in place. It will be understood that when the stairway is fully constructed all joints should be smooth. The steps of the present invention require only a small base, such as four cement blocks on each corner having their upper surfaces level with each other and a 6 inch gravel or crushed rock base under them. This will prevent frost heave and assure a square level step. The steps should not be used for approximately 24 hours in order to give time for the mortar to dry and bond the parts together securely. Thereafter the steps are ready to be used.

In the production of the stairway, bottoms are provided for a given number of side forms so that after one side form is filled it can be removed leaving the set-up material on the bottom or base and the side form used again until the desired number of step sections are produced and then these step sections are rolled into a storage area to be allowed to set until cured.

We claim:

1. Molded members for constructing a stairway comprising a pair of side members of predetermined thickness disposed in spaced generally parallel relationship, each of said side members having at least one first flat generally horizontal portion for supporting a riser member and at least one offset generally parallel second horizontal portion for supporting a tread member, an elongated riser member having an upper portion and a lower portion, the ends of the lower portion of said riser member being inwardly ofiset from the ends of said upper portion a distance substantially corresponding to the predetermined thickness of said side members, the ends of the upper portion of said riser engaging the first portion of each of said side members and the ends of said lower portion substantially abutting said side members, the top of the upper portion of said riser member being substantially in alignv as long as said riser member and a second portion of a length corresponding generally to the length of the lower portion of said riser member, the first portion of said tread member engaging and supported by said second horizontal portions of said side members and the upper portion of said riser member, the second portion of said tread member being located between and substantially abutting said side members, and means for bonding said members together in assembled relationship.

2. The structure of claim 1 including a platform having a length corresponding generally to the length of the first portion of said tread member and disposed on top of said side members.

3. The structure of claim 1 in which the exposed exterior surfaces of said side members and riser member have an ornamental appearance including a plurality of intersecting grooves so that the exterior surfaces simulate bricks, and cementitious material in said grooves simulating mortar.

4. The structure of claim 1 in which the bottom of the lower portion of said riser member overlies and substantially abuts the second portion of an underlying tread member. 

1. Molded members for constructing a stairway comprising a pair of side members of predetermined thickness disposed in spaced generally parallel relationship, each of said side members having at least one first flat generally horizontal portion for supporting a riser member and at least one offset generally parallel second horizontal portion for supporting a tread member, an elongated riser member having an upper portion and a lower portion, the ends of the lower portion of said riser member being inwardly offset from the ends of said upper portion a distance substantially corresponding to the predetermined thickness of said side members, the ends of the upper portion of said riser engaging the first portion of each of said side members and the ends of said lower portion substantially abutting said side members, the top of the upper portion of said riser member being substantially in alignment with said offset second horizontal portions of said end members and forming a support for a tread member, a tread member having a first portion at least as long as said riser member and a second portion of a length corresponding generally to the length of the lower portion of said riser member, the first portion of said tread member engaging and supported by said second horizontal portions of said side members and the upper portion of said riser member, the second portion of said tread member being located between and substantially abutting said side members, and means foR bonding said members together in assembled relationship.
 2. The structure of claim 1 including a platform having a length corresponding generally to the length of the first portion of said tread member and disposed on top of said side members.
 3. The structure of claim 1 in which the exposed exterior surfaces of said side members and riser member have an ornamental appearance including a plurality of intersecting grooves so that the exterior surfaces simulate bricks, and cementitious material in said grooves simulating mortar.
 4. The structure of claim 1 in which the bottom of the lower portion of said riser member overlies and substantially abuts the second portion of an underlying tread member. 